Evaluating
new traits for potato in the Central Andes with an appropriate poverty focus

Background
and objectives

There are large potato yield losses caused by indigenous nematode pests
in the central Andes. It is possible to counter this problem by genetic
modification. Resistance to the pest can be conferred on potato roots
by the expression of genes from other food crops (e.g. rice and maize).
Nematode control has been achieved in UK field trials and did not cause
any adverse effects on non-target insects. This project aims to evaluate
the risks to non-target animals and soil micro-organisms in the central
Andes. Biosafety risks, common to all genetically modified organisms,
will be considered. Risks to non-target organisms and of genetic
pollution are to be determined. These include the risk of transferring
modified genes into wild relatives of the potato via pollen. A cautious
approach should be adopted to assess and minimise this risk. The aim is
to determine whether genetically modified potatoes can be grown in the
central Andes with a high level of environmental biosafety.

A
potato plant in a greenhouse trial.Photo: PBIU, University of Leeds.

A
Bolivian farmer examining a nematode-infested potato crop. A significant
proportion of the crop is lost to nematode damage each year.Photo: PROINPA.

Open
cyst with eggs of the Globodera pallida, known as the potato
cyst nematode.

On
a normal host the nematodes feed on plant roots and grow normally.
They become enlarged with eggs.

Transgenic
resistance prevents the nematodes from digesting their food properly.
Without adequate nutrition they are unable to grow to their normal
egg-laying size.

Approach and methodology

Previously developed methods will be used to quantify the risks of genetic
transfer from genetically modified organisms to non-target organisms. Models
to be studied include bumblebees, earthworms and various predators. It is
important to determine the amount of gene transfer between the genetically
modified potato and its wild relatives because they are sexually compatible.
Gene transfer in potatoes will be measured as a function of planting distance
by berry number on a male sterile cultivar. For weed species, AFLP molecular
markers will be used to quantify gene transfer. The feasibility of reducing
introgression to negligible levels by use of male and female sterile potato
cultivars will be determined. If biosafety is assured and consent is obtained
from growers and consumers, nematode resistance will be offered on a royalty-free
basis to farmers with poor resources.